Fake SNS Module to be used in local laboratory - To real utilisation, replace the implementation to call the AWS SNS SDK

fake-sns.js

'use scrict'

\**
* https://repl.it/@marquesanderson/fake-sns
*\

const events = require('events')
const eventsEmitter = new events.EventEmitter()

class SNSPublisher {
  constructor (topic) {
    this.topic = topic
  }

  publish (message) {
    console.log(`Publishing message=${JSON.stringify(message)} to topic: ${this.topic}`)
    eventsEmitter.emit(this.topic, {
      'Records': [
        {
          'EventVersion': '1.0',
          'EventSubscriptionArn': 'arn:aws:sns:fake-sns',
          'EventSource': 'aws:sns',
          'Sns': {
            'SignatureVersion': '1',
            'Timestamp': '1970-01-01T00:00:00.000Z',
            'Signature': 'fake-signature',
            'SigningCertUrl': 'fake-cert-url',
            'MessageId': '95df01b4-ee98-5cb9-9903-4c221d41eb5e',
            'Message': JSON.stringify(message),
            'MessageAttributes': { },
            'Type': 'Notification',
            'UnsubscribeUrl': 'fake-url',
            'TopicArn': `arn:aws:sns:fake-sns:this.topic`,
            'Subject': 'FakeInvoke'
          }
        }
      ]
    })
  }
}

class SNSSubscriber {
  constructor (topic, callback) {
    eventsEmitter.on(topic, (event) => {
      callback(JSON.parse(event.Records[0].Sns.Message))
    })
  }
}

const producer = new SNSPublisher('some-topic')
const consumer1 = new SNSSubscriber('some-topic', (message) => {
  console.log(`Consumer 1 - Message received: ${message}`)
})

const consumer2 = new SNSSubscriber('some-topic', (message) => {
  console.log(`Consumer 2 - Message received: ${message}`)
})

producer.publish('Hello World')